During A330 training, various instructors will have many different types of equations and gateways used to confirm the descent profile and whether or not they are above or below glidepath.

The equations that I used now are

$$ \text{Wind} = \pm 1 \, \text{NM per} \; 5 \; \text{knots (head- or tailwind)} $$

$$ \text{Bleed off Speed} = 1 \, \text{NM per} \; 10 \; \text{knots or} \; 1.5 \, \text{NM per} \; 10 \; \text{knots during descent} $$

$$ \text{TOD} = \frac{\text{Altitude}}{1000} \times 4 $$

But I understand you would have to consider the aircraft weight, temperature, flap settings etc. but I'm not sure how to or even know where to start with that.

Would like to know your calculation or methodology! Any references would also be great!

  • 1
    $\begingroup$ Have you tried reading the Airbus document Getting to Grips with Aircraft Performance? $\endgroup$
    – Gerry
    Jan 7, 2020 at 12:25
  • $\begingroup$ I have seen it during training...but realistically speaking, its abit difficult to mentally calculate in-flight :/ I know you dont really have to calculate much as you can just monitor and understand the plane as it flies, but just need like aa approximate formula or like gateway reference $\endgroup$ Jan 10, 2020 at 15:07


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